Optimization Of Process Parameters For Deep Drawing Of The Laser Tailored Door Inner Panel

With the great development of the automobile industry,the environmental pollution and energy shortage have become increasingly prominent in recent decades.Automobile lightweight tends to be important for automobile industry from now on.The tailor-welded blank stamping technology,the new technology to achieve lightweight of automotive,has gradually attracted the attention of major automotive companies and research institutions.However,due to the existence between different base material and weld zone,the material properties of tailor-welded blanks varied greatly.In the process of stamping forming,it led to defects such as cracking,wrinkling and weld moving.In this paper,the inner panel of a car rear door was taken as the research object.The elastoplastic mechanical properties of the base material and weld zone of the tailor-welded blanks were measured by uniaxial tensile test and metallographic microscopy.Combined with the cupping test,the forming properties of the tailor-welded blanks and the single homogeneous base material were analyzed.The finite element software was used to analyze the comparative experiments of drawbeads with different resistance coefficients,and the optimal layout scheme of drawbeads was given.It was a reference for optimizing the forming process parameters of the rear door panel and improving the manufacturing quality of automobile body.Based on the structural characteristics of the rear door inner panel,the rational stamping direction,pressing surface,supplementary addendum surface and drawbeads were designed,and the corresponding finite element drawing model was constructed.According to the initial simulation results,a "step" die structure was designed.Furthermore,the distance between the die steps and the initial weld line,the blank holder force,the die clearance and other forming parameters were further optimized,so as to greatly reduce the weld-line movement and optimize the overall forming effect.Relied to the theoretical research that the process incision can effectively release the local stress concentration of the sheet metal,the influence of the type,size,position and opening time of the process incision on the sheet metal deep drawing were analyzed.According to the theoretical analysis of the mesh algorithm,the key words of the piercing process in the finite element analysis were given,and the simulation analysis of the piercing process of the rear door inner plate was realized.Finally,the acceptable drawing parts of the rear door inner plate were obtained.